Some optical properties of the multilayer system: a helical periodical medium layer (1) (HPML(1))-an isotropic dielectric layer (IDL)-HPML(2) are discussed. HPML is in external magnetic field and due to this it becomes nonreciprocal. The electromagnetic wave energy distribution peculiarities inside the system are investigated as well. It is shown that wave energy accumulation takes place in certain spectral regions. Multilayer optical systems based on realistic materials with periodical structure are also discussed under the scope of applications for liquid or gas-heaters and for using as a solar energy and fiber optics converters.